Concurrent Expert Evidence: Still Flavour of the Month?
2018 IPSANZ Annual Conference
This short piece was adapted from a presentation given by the Honourable Justice John Middleton at the 32nd IPSANZ Annual Conference on 9 September 2018.
The purpose of this brief paper and the question asked in its title is to promote discussion about the benefits and drawbacks of concurrent expert evidence and to ask whether the so-called 'hot tub' method is still attractive amongst intellectual property lawyers.
Much has been written concerning the use of concurrent evidence at trials and so I am going to assume that readers will be familiar with the process of preparing concurrent evidence and the giving of concurrent evidence in trial – see generally the Honourable Justice Steven Rares, 'Using the "Hot Tub": How Concurrent Expert Evidence Aids Understanding Issues' (2011) 10 The Judicial Review 171; Adam Butt and Hugh Stowe, 'Playing in the Hot Tub – A Guide to Concurrent Expert Evidence in New South Wales'  (Spring) Bar News 44–55.
I am also going to assume that it is generally accepted that the giving of concurrent evidence has many advantages, including enabling all those involved in the trial to hear the experts discussing the same issues at the same time, which enhances the comprehension and exploration of the evidence, especially by the bench.
The effectiveness of the giving of expert evidence in the Federal Court of Australia is buttressed by the Harmonised Expert Code of Conduct which emphasises that the experts have a duty to the court – not the party that retained them – and to act impartially at all times. Courts in other Australian jurisdictions maintain similar codes of conduct in respect of expert evidence.
Some may be sceptical about the extent to which an expert called by and paid by a party would adhere to such codes but in practice, I think in the main, they are adhered to.
However, despite the obvious advantages of concurrent expert evidence, there has been in some quarters a resistance to the use of concurrent expert evidence and some of that resistance can be summarised as follows:
- The exclusion of lawyers from expert conclaves and the problems that may arise as to defining the issues for the experts.
- Even though rules of court provide for procedural guidelines, there is uncertainty and lack of structure as to the process, particularly at the hearing itself.
- There is the concern that the personality of one expert may overbear the personality of another expert – see, for example, Britax Childcare Pty Ltd v Infa-Secure Pty Ltd (No 4).
- There is the concern that in some cases it may be necessary to cross examine the expert as to creditability and this may not fit in with the way in which concurrent expert evidence is given.
- There are the cost implications in certain cases which may not justify the use of concurrent expert evidence and the joint report.
- The timing of expert conclaves can be significant and the parties may not have the opportunity to arrange their experts to appropriately meet and discuss their reports.
- There is the issue of whether or not concessions in a joint report should be able to be resiled from.
- There is the concern about the role of the judge, particularly as to whether he or she is too interventionist during the course of the giving of concurrent expert evidence.
In addition to these matters, there has been the issue in jury trials (both civil and criminal) whether or not concurrent evidence would be appropriate. In America, this issue has elicited different reactions from various judges. One view is that concurrent evidence in jury trials would be inappropriate, while other judges feel comfortable in using experts in a conclave before a jury as long as the matter is managed carefully by giving appropriate directions. The judge ordinarily must be careful not to inappropriately intervene in jury trials, particularly in the case of criminal jury trials.
There are other concerns with concurrent expert evidence. They are:
- The experts may not deal with all the issues that parties consider relevant.
- The experts may not deal with all the issues the judgment has to address.
- The experts will not have the opportunity to prepare a report based on the correct facts.
- The joint report may represent two individual reports collated by a few covering pages or a series of unreasoned assertions by each expert.
- Some judges like to have the opportunity of assessing an expert being cross examined in the normal way.
As to the last point, I should say that the current approach seems to be cautious about drawing conclusions too readily concerning truthfulness or reliability based on the appearance of witnesses. In Fox v Percy, the High Court approved the observation of Atkin LJ in Societe d'Avances Commerciales (Societe Anonyme Egyptienne) v Merchants' Marine Insurance Co ('The Palitana'):
I think that an ounce of intrinsic merit or demerit in the evidence, is to say, the value of the comparison of evidence with known facts, is worth pounds of demeanour.
Another issue that has been raised recently is the use of assessors, although they could be used even when one has the advantage of concurrent evidence. Engaging an independent assessor whose sole duty is to the court can have additional benefits to the joint meeting of experts, joint reports and concurrent evidence sessions. Assessors appointed by the court can perform a variety of functions at the discretion of the judge at the pre-trial, trial and post-trial stage of proceedings – see generally the comments of J Forrest J in Matthews v SPI Electricity Pty Ltd (No 19), and the related Matthews v SPI Electricity Pty Ltd (No 32).
The functions performed by assessors appointed by the court may include:
- acting as a human primer to deliver tutorials to the judge, explaining some questions that a judge might have concerning technical evidence;
- sitting with the judge to listen to the expert evidence;
- assisting the judge in relation to complex technical matters;
- putting questions directly to counsel or witnesses at the hearing or suggesting questions for the judge to put to counsel or witnesses;
- conferring with judge to get the technical concepts correct; and
- reviewing draft judgments for technical accuracy.
A suggestion has also been made that it may be better to introduce depositions so that prior to the expert giving evidence, the opposing party has the opportunity of examining the expert with a view to determining and reducing the issues that need to go to trial. The use of depositions in America is said to have a number of advantages including the aim of finding out information, encouraging witnesses to make admissions, and then once key witnesses (including the experts) on both sides have been deposed, the case may be evaluated from an educated position, which may ultimately lead to summary judgment, settlement between the parties, or at the very least remedying some deficiencies in the underlying case. I will not go into the advantages and disadvantages of depositions in an Australian setting – the prime disadvantage being of course cost and abuse.
So, to answer the question "Is concurrent expert evidence still flavour of the month?" I think in most instances the advantages outweigh the disadvantages.
It all depends upon the case, and in some situations the normal process of examination, cross examination and re-examination may still be the most efficient and effective method for adducing expert testimony and informing the bench. Ultimately, it will be for the practitioners of intellectual property law to, in any given case, determine how best to present their client's case and represent their client's interests, subject to the interests of efficiency, expedition and the administration of justice.
 (2015) 113 IPR 280.
 See, eg, Adam Butt, 'Concurrent Expert Evidence in U.S. Toxic Harms Cases and Civil Cases More Generally: Is there a Proper Role for Hot Tubbing?' (2017) 40(1) Houston Journal of International Law 1, 26–28.
 (2003) 214 CLR 118, 128–9 –.
 (1924) 20 Ll L Rep 140, 152.
  VSC 180 (18 April 2013).
  VSC 630 (18 November 2013).
 See, eg, Michael Legg, 'The United States Deposition – Time for Adoption in Australian Civil Procedure?' (2007) 31(1) Melbourne University Law Review 146.